“Jurassic Park,” adapted from Michael Crichton’s conceptually brilliant novel, is a horror movie wrapped in the trappings of early ’90s speculative science. Back then, kids were dino mad, the magical letters “DNA” were on every research grant, and the wonders of genetic code were just beginning to unravel.

What a great time for a scary movie about a tycoon (Richard Attenborough) whose efforts have led to the breakthroughs that enable him and his backers to open an island theme park where dinosaurs have been back-engineered back to life.

Not that they should have been.

Things, as Malcolm predicts, will go wrong. Storms happen, cages fail, “sterile” dinosaurs turn out not to be. And people, who never walked the Earth at the same time as these beasties, are now the main item on the menu. Chaos theory incarnate.

Steven Spielberg’s film captures the terror in thunderous approaching footsteps, in breathy sniffs from a nose as powerful as an air compressor. The dinosaurs, impressive in their animated actions and leathery digital texture in ’93, haven’t lost much of their moist, tactile menace over the decades.

The frights still work, supersized and turned into 3D for your viewing and recoiling-from-the-screen pleasure.

If anything, science has closed the gap from the impossible to the merely improbable in the 20 years since this movie reminded us of “When Dinosaurs Ruled the Earth.” Australians are close to bringing back a recently extinct species of frog, and others are working to bring back the day when dodos ruled the Earth.

Good idea? Maybe to some. But that’s where Goldblum comes in handy. Nobody explained the improbable, and the risks involved in it, like Goldblum’s Dr. Malcolm.

“Oh, yeah. ‘Oooh, ahhh,’ that’s how it always starts. Then later there’s running and screaming.”